1. Field of the Invention
The present invention relates to a chest drainage system, and particularly to a dry chest drainage apparatus for suctioning gases and liquids from the chest cavity of a patient. More specifically, the present invention relates to a vacuum setting and indication system for a dry chest drainage apparatus which permits viewing by the user from a number of directions.
2. Prior Art
A chest drainage device is an apparatus for suctioning gases and liquids from the pleural cavity of patients. The pleural cavity lies within the rib cage above the diaphragm and is surrounded by the pleural membrane. The pleural cavity contains both lungs, which in their normal expanded state fill the pleural cavity. Several conditions and diseases such as interventional surgery, trauma, emphysema and various respiratory infections can cause build up of liquid and gases around the lungs in the intrapleural space. When this happens, it causes the lungs to collapse to a volume much less than that of the pleural cavity, thereby severely impairing the breathing functions of the patient. The lungs can be re-expanded to their normal state to fill the pleural cavity by draining the liquid and gases from the intrepleural space using a chest drainage device.
There are many kinds of chest drainage devices used to drain the intrapleural space of a patient. One kind of drainage device, sometimes referred to as a “three-bottle” type, is illustrated in U.S. Pat. No. 3,363,626 to Bidwell et al. entitled “Underwater Drainage Apparatus”. The “three-bottle” type drainage device has three interconnecting chambers which comprise: (1) a collection chamber for collecting liquids and gases suctioned from the patient's pleural cavity; (2) an underwater seal chamber which communicates with the collection chamber and has a water seal which acts as a one way valve for passing gases from the patient's pleural cavity to the atmosphere; and (3) a suction control chamber for limiting the maximum suction (or negative pressure) applied to the patient's pleural cavity.
Another kind of drainage device is the “four-bottle system” which includes the three chambers of the “three-bottle system” and adds a fourth chamber, referred to as a manometer chamber, which provides an accurate indicia of the level of suction being applied to the cavity to be drained. However, the “four-bottle system” suffers from several deficiencies. In particular, the suction control chamber is noisy due to bubbling of atmospheric air through the liquid maintained therein; and the system is somewhat bulky.
With increased awareness of the anxiety-provoking nature of noise in the hospital environment, a mechanical regulator to adjust the level of vacuum applied was provided as a substitute for a liquid filled suction control chamber of the prior art. U.S. Pat. No. 4,372,336 to Cornell discloses a mechanical regulator for a drainage device having a liquid-filled manometer chamber which provides a visual indication of the vacuum level present in the device. Although the drainage device of Cornell is an improvement over prior art drainage devices, such devices could still be further improved. For example a drainage device having a dry system containing no liquid in either the suction control chamber or manometer chamber would be desirable.
Drainage devices employing a dry system for draining liquid and gases from a patient's pleural cavity use a mechanical regulator to both adjust the level of vacuum to the device as well as a means of indicating the actual degree of vacuum being applied to the drainage device. Such drainage devices normally have a dial or knob disposed along either the side or front wall of the drainage device casing for adjusting the degree of vacuum by rotating the dial or knob in one direction. U.S. Pat. No. 4,784,642 to Everett, Jr., et al. and U.S. Pat. No. 5,989,234 to Valerio, et al. are illustrative of drainage devices using a mechanical regulator in the form of a rotatable dial or knob on the front or side of the device to adjust the level of vacuum in the device. However, such prior art adjustment means are difficult to view from different angles and are cumbersome to operate since these mechanisms have mechanical arrangements that can become stuck or require extra effort to operate, while the vacuum setting indicia surrounding the knob dial can only be viewed from the front or side of the device.
Some drainage devices are also provided with a vacuum indicator assembly to visually indicate the presence of vacuum inside the drainage device. Vacuum indicator assemblies can be in the form of an extendable baffle, a floating ball chamber or an inflatable masking diaphragm which provides a selective visual signal to the user of proper vacuum in the drainage device. Similar to the vacuum indicator assembly disclosed in U.S. Pat. No. 4,747,843 to Felix et al., vacuum indicator assemblies of the prior art are recessed along the front or top portions of the drainage device, thereby making them strictly viewable from a limited angle.
The drawback of having either the vacuum indicator assembly or vacuum setting indicia being recessed inside the drainage device along either the side or top portion thereof is that a user may not be able to clearly view either the indicator assembly or setting indicia when the drainage device is placed on the floor or a desk, or suspended from a pole. In other words, when the drainage device is placed on the floor, the user cannot view the vacuum indicator assembly if the assembly is located along the side of the device, and thereby hidden from view.
Therefore, there is a need in the art for a drainage device having a mechanical regulator which gives a clear indication of the vacuum level setting to the user from a number of angles. There is a further need in the art for a drainage device having a vacuum indicator assembly that is clearly viewable from many directions by the user.